MD5加密(C语言版、实测)

头文件中:

#define shift_(x, n) (((x) << (n)) | ((x) >> (32 - (n)))) //右移的时候，高位一定要补零，而不是补充符号位
#define F_(x, y, z) (((x)& (y)) | ((~x) & (z)))
#define G_(x, y, z) (((x)& (z)) | ((y)& (~z)))
#define H_(x, y, z) ((x) ^ (y) ^ (z))
#define I_(x, y, z) ((y) ^ ((x) | (~z)))
#define A_ 0x67452301
#define B_ 0xefcdab89
#define C_ 0x98badcfe
#define D_ 0x10325476

//md5加密
 //strBaye的长度
 unsigned int strlength;
 //A,B,C,D的临时变量
 unsigned int atemp;
 unsigned int btemp;
 unsigned int ctemp;
 unsigned int dtemp;
 //常量ti unsigned int(abs(sin(i+1))*(2pow32))

 void mainLoop(unsigned int M[]);
 unsigned int* add(string str);
 string changeHex(int a);
 string getMD5(string source);

Cpp中：

const unsigned int k[65] = {
 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
 0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501, 0x698098d8,
 0x8b44f7af, 0xffff5bb1, 0x895cd7be, 0x6b901122, 0xfd987193,
 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340, 0x265e5a51,
 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905,
 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681,
 0x6d9d6122, 0xfde5380c, 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60,
 0xbebfbc70, 0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x04881d05,
 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665, 0xf4292244,
 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92,
 0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314,
 0x4e0811a1, 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391 };
//向左位移数
const unsigned int s[65] = { 7, 12, 17, 22, 7,
12, 17, 22, 7, 12,
17, 22, 7, 12, 17,
22, 5, 9, 14, 20,
5, 9, 14, 20, 5,
9, 14, 20, 5, 9,
14, 20, 4, 11, 16,
23, 4, 11, 16, 23,
4, 11, 16, 23, 4,
11, 16, 23, 6, 10,
15, 21, 6, 10, 15,
21, 6, 10, 15, 21,
6, 10, 15, 21 };
const char str16[17] = "0123456789abcdef";

void CSQLiteUtil::mainLoop(unsigned int M[])
{
 unsigned int f, g;
 unsigned int a = atemp;
 unsigned int b = btemp;
 unsigned int c = ctemp;
 unsigned int d = dtemp;
 for (unsigned int i = 0; i < 64; i++)
 {
  if (i<16){
   f = F_(b, c, d);
   g = i;
  }
  else if (i<32)
  {
   f = G_(b, c, d);
   g = (5 * i + 1) % 16;
  }
  else if (i<48){
   f = H_(b, c, d);
   g = (3 * i + 5) % 16;
  }
  else{
   f = I_(b, c, d);
   g = (7 * i) % 16;
  }
  unsigned int tmp = d;
  d = c;
  c = b;
  b = b + shift_((a + f + k[i] + M[g]), s[i]);
  a = tmp;
 }
 atemp = a + atemp;
 btemp = b + btemp;
 ctemp = c + ctemp;
 dtemp = d + dtemp;
}
/*
*填充函数
*处理后应满足bits≡448(mod512),字节就是bytes≡56（mode64)
*填充方式为先加一个1,其它位补零
*最后加上64位的原来长度
*/
unsigned int* CSQLiteUtil::add(string str)
{
 unsigned int num = ((str.length() + 8) / 64) + 1;//以512位,64个字节为一组
 unsigned int *strByte = new unsigned int[num * 16];    //64/4=16,所以有16个整数
 strlength = num * 16;
 for (unsigned int i = 0; i < num * 16; i++)
  strByte[i] = 0;
 for (unsigned int i = 0; i <str.length(); i++)
 {
  strByte[i >> 2] |= (str[i]) << ((i % 4) * 8);//一个整数存储四个字节，i>>2表示i/4 一个unsigned int对应4个字节，保存4个字符信息
 }
 strByte[str.length() >> 2] |= 0x80 << (((str.length() % 4)) * 8);//尾部添加1 一个unsigned int保存4个字符信息,所以用128左移
 /*
 *添加原长度，长度指位的长度，所以要乘8，然后是小端序，所以放在倒数第二个,这里长度只用了32位
 */
 strByte[num * 16 - 2] = str.length() * 8;
 return strByte;
}
string CSQLiteUtil::changeHex(int a)
{
 int b;
 string str1;
 string str = "";
 for (int i = 0; i<4; i++)
 {
  str1 = "";
  b = ((a >> i * 8) % (1 << 8)) & 0xff;   //逆序处理每个字节
  for (int j = 0; j < 2; j++)
  {
   str1.insert(0, 1, str16[b % 16]);
   b = b / 16;
  }
  str += str1;
 }
 return str;
}
string CSQLiteUtil::getMD5(string source)
{
 atemp = A_;    //初始化
 btemp = B_;
 ctemp = C_;
 dtemp = D_;
 unsigned int *strByte = add(source);
 for (unsigned int i = 0; i<strlength / 16; i++)
 {
  unsigned int num[16];
  for (unsigned int j = 0; j<16; j++)
   num[j] = strByte[i * 16 + j];
  mainLoop(num);
 }
 return changeHex(atemp).append(changeHex(btemp)).append(changeHex(ctemp)).append(changeHex(dtemp));
}

调用方式：

int main(){

　　string szDigest;

　　char *encrypt = new char[2];
　　encrypt = "0";
　　 // 加密
　　 szDigest = getMD5(encrypt);　　

}Test结果：szDigest 为 cfcd208495d565ef66e7dff9f98764da 。

加密成功。

                                                                                                                                                                                                                                        SYQ.

MD5加密(C语言版、实测)